Slip ring assemblies are used in the automotive industry to transfer power from the brushes to the coil of an alternator. A typical slip ring assembly, like that disclosed in U.S. Pat. Nos. 5,327,037 and 4,535,264, includes a molded body made from electrically insulating plastic, one or more electrically conductive slip rings mounted around the outside of the body, and two electrical terminals embedded in the plastic body and electrically connected to the slip rings.
The assembly body is usually molded out of either a polyester or phenolic plastic. Slip ring assemblies with bodies made of polyester plastic often fail catastrophically because they are not strong enough to withstand the dynamic loading they receive while in use, especially at elevated temperatures and high rotational speeds. Slip ring assemblies with bodies made of phenolic plastic are typically strong enough to survive such adverse conditions. However, phenolic plastic bodies are more expensive to produce than polyester plastic bodies.
Accordingly, there is a need for an improved slip ring assembly that is relatively inexpensive to produce but still suitably resistant to catastrophic failure, while being subjected to applied loads under severe operating conditions, such as high rotational speeds, elevated temperatures and the like.